Some fuel dispensing systems include multiple-grade fuel sources with single or multiple fuel outlets for dispensing various grades of fuel. Each fuel source may include a pump to dispense the fuel from its source to its respective meter for measuring the volume of fuel. The fuel then remains in its original concentration or it is blended with other fuels to form a separate concentration before reaching the fuel outlet. A problem with these systems occurs when a single fuel outlet or fuel line dispenses multiple grades of fuel. Lower grades of fuel can remain in the system while the user attempts to obtain a higher grade of fuel. This contamination can often present a lower grade of fuel than required. One solution is to leave the lower grade of fuel in the system and combine it with higher grade, hoping that the combination would have sufficient grade to satisfy state and federal regulations. However, this can be disadvantageous for users who only dispense a small volume of fuel since the volume within the system creates a large variation on the grade of the fuel and places a design limitation on the system due to the small volume. Another solution is to place residual high grade fuel in the system in order to compensate for the lower grade fuel previously dispensed. However, this can complicate the system and fail to give the user the expected grade of fuel when the highest grade has been selected or a small volume is desired.
U.S. Pat. No. 5,908,055 discloses a fuel dispenser for dispensing different types of fuel. The fuel dispenser has a dispenser housing and a fuel pumping unit for each type of fuel to be dispensed mounted in the dispenser housing. The fuel dispenser further has a hose comprising three separate fuel lines for dispensing three various grades of fuel. A problem with such a hose is that it requires a large diameter which makes the hose inflexible. Another problem is that since the fuel lines will have to be small in order to fit within the hose, the fuel flow rate in said fuel lines will be limited.